A vehicle including an oil cooler and a bypass oil passage that circumvents the oil cooler is conventionally known. For example, Patent Literature 1 discloses an oil temperature control device of a vehicle in which an oil passage connecting an ATF cooler with a warmer function and the ATF cooler includes a bypass oil passage that circumvents the ATF cooler, and a switching control valve that selectively switches oil passages based on a control signal output from a control unit is arranged at a branched portion of the oil passage and the bypass passage.
The control unit of Patent Literature 1 determines whether or not the oil temperature of an automatic fluid discharged from the ATF cooler with the warmer function reached a set temperature set in advance, and outputs a control signal for communicating the ATF cooler, with the warmer function and the ATF cooler if the oil temperature reached the set temperature set in advance and outputs a control signal for communicating the ATF cooler with the warmer function and the bypass oil passage if the oil temperature has not reached the set temperature set in advance.